The packaging of slurry explosive compositions in plastic bags is one important method for distributing such explosives as saleable products. Plastic bags which can be easily fabricated by side sealing with available packaging apparatus are an especially efficient means for producing such products. In the past, flexible polyvinyl chloride film has been used successfully to package water-in-oil emulsion type slurry explosive compositions. An example of such packaging materials include the skin tight packages described in U.S. Pat. No. 3,731,625 to Slawinski.
Referring especially to water-in-oil type emulsion explosive compositions, recently improved products of this variety have been discovered which employ void producing materials as sensitizing agents in place of the occluded air or other gases which have been used in emulsion explosives in the past. Examples of this new improved type of emulsion explosive are set forth in U.S. Application Ser. No. 848,333, filed Nov. 3, 1977. These new explosive emulsion compositions are processed at significantly higher temperatures than were conventional emulsion explosive compositions. Thus, temperatures of 150.degree. to 200.degree. F. are normally employed and packaging operations normally will occur at these higher temperatures. Such higher temperatures adversely affect the structural properties of polyvinyl chloride films and may cause swelling which produces an air space or sag in the package which is both unattractive and may affect the propagation of the explosive from one container to the next when a plurality of explosive packages are stacked in a borehole. Thus packaging films which can be employed with conventional types of packaging apparatus, in order to automate packaging operations, and which retain good structural integrity at temperatures in the range of from about 150.degree. to 200.degree. F. are desirable.
Another requirement for packaging films which are employed with emulsion explosive compositions is that the film be resistent to degradation which can result from contact of some plastics with the external oil phase of such explosive compositions. Continual contact of the film package with the external oil phase can cause swelling and wrinkling of the package under storage conditions. Thus resistance to such degradation is a required characteristic for useful packaging films.
Finally, the packaging film for the emulsion explosive compositions must be strong enough to resist rupture upon impact when dropped during normal handling or under field usage conditions.